8 must-know facts about China's air pollution crisis

2. Cities in China’s Yangtze River Delta, Pearl River Delta, and Beijing-Tianjin-Hebei region suffered over 100 hazy days a year with PM2.5 concentration two to four times above World Health Organization guidelines.

3. Beijing experienced 2,589 deaths and a loss of US$328 million in 2012 because of PM2.5 pollution.

4. In May 2012, Beijing announced a coal-consumption cap of 15 million tonnes by 2015.

5. On December 5, the Chinese Ministry of Environmental Protection (MEP) announced a 350 billion yuan (US$56 billion) plan to reduce air pollution during the 2011-2015 period.

6. Particles less than 2.5 micrometers in diameter are called "fine" particles. These particles, approximately 1/30 the average width of a human hair, can lodge deeply into the lungs. Sources of fine particles include all types of combustion, including power plants, motor vehicles and residential wood burning.

7. Wearing N95 masks will provide effective protection against PM2.5 air pollution but ensure you are wearing the mask correctly with a tight seal around the face. N95 masks can be purchased in pharmacies and can be used multiple times.

8. With 16-26% of inhalable particles contributed from sources outside of one's city it's important that the governments regionally co-ordinate plans, something only the cities of the Pearl River Delta has tried to do.